1. Field of the Invention
The present invention relates to a head-protecting airbag which, when fed with inflation gas, is deployable downward from upper edge of side windows of a vehicle to protect occupants' heads.
2. Description of Related Art
In the prior art, Japanese Patent Laid-Open No. Hei 11-321528 is illustrative of a head-protecting airbag which is folded and housed above side windows, and is deployable to cover side windows while unfolding when fed with inflation gas.
This head-protecting airbag includes an inner wall and an outer wall which form a gas admissive portion that admits inflation gas therein. From a flatly developed state with the inner wall and outer wall overlaid on each other, the airbag is folded in a bellows of a certain width to bring its lower edge close to its upper edge. Then the airbag is housed between a roof head lining and an inner panel as part of a vehicle body above side windows.
Although airbags thus housed swiftly unfold and deploy when fed with inflation gas, differences of vertical dimensions in various parts of the airbags and slight errors in folding width tend to vary positions of lower edges of completely folded airbags from airbag to airbag. For example, one airbag is directed toward a vehicle's interior, and another is directed toward a vehicle's exterior at the lower edge.
In an initial stage of inflation, the airbags thus housed tend to protrude in directions to which lower edges of the airbags are directed, and protruding directions are not uniform. Therefore, the airbags need to be improved to deploy uniformly and smoothly in clearances between side windows and occupants' heads even in a case where the clearances are narrow.